Parasitic microorganisms of Japanese beetle (Coleoptera: Scarabaeidae) and associated scarab larvae in Connecticut soils

Abstract

The parasites of 2nd and 3rd instar Popillia japonica and associated scarab larvae were identified in turf samples. Four of the 7 species of scarab larvae encountered were introduced and accounted for 91% of the sample population. Recovered parasites included 3 species of protozoa, 2 bacteria, a rickettsia, and a fungus. The most common protozoa, cephaline eugregarines, were found in the gut of Japanese beetles from 42 locations, and in 4 other host species. A microsporidium, Ovavesicula popilliae, was found in Japanese beetles from 34 sites. Overall, 25% of larvae were infected, but prevalance was 80-90% in some locations. An Adelina sp. infecting 19% of the Asiatic garden beetles, Maladera castanea, was found at 6 locations and in 2 other scarab species. The bacteria Bacillus popilliae and B. lentimorbus, and Rickettsiella popilliae were also recovered from grubs. Two of the infected species, Asiatic garden beetle and European chafer, Rhizotrogus majalis are new records as natural hosts for this rickettsia. The incidence of B. popilliae (3.5%) was comparable with previous reports from Connecticut. The fungus Metarhizium anisopliae infected 1.2% of the Japanese beetles. -from Authors